~ Additive Manufacturing and Technology

Monthly Archives: January 2015

I managed to print a 20mm calibration cube using some ABS filament other than what was sent with the machine. The part came out with some interesting defects (the side walls showed definite herringbone patterns, suggesting insufficient drive to the extruder motor) however the X and Y accuracy was pretty good. But as I unloaded the filament at the end of the job, it was obvious that I too now had the “loose screw” in the drive wheel problem.

Fixing that is not difficult – take the plastic cover off and the left side of the extruder body using the two thumbscrews. Then take the fan on the right side off and it will uncover some slits where you can easily insert a 1.5mm allen wrench. Of course you’ll have to get the drive wheel in the correct place on the stepper motor shaft, as well as the proper front spacing.

Pictures coming soon. Note also Solidoodle released an update (1.1.1 now) to the client software on 2/12 or so) – it fixes some issues reported so far.

UPDATE: while I get my video properly edited, here are the things you can do to improve your head cable:

1. Remove (and discard!) the factory supplied black cable loom piece – if it is like mine, it is too stiff, too large, and too big in diameter. It just gets in the way.

2. Use a tywrap to fix the cable bundle at the head to the top side of the extruder motor. I also used some hot melt glue as an enhancement. The wires should come off of the left side of the head, low and with enough give for the Z probe to move.

3. Use some tywraps to make the cable bundle secure along its length back to where the wires enter the chassis.

3. Fix an elastic string (I got some at a fabric shop) to the cable bundle about midway, and hot melt glue it there and to the front left corner of the chassis. There will be some need for experimentation for the best “preload.” What this does is keep the cable assembly tensioned so that it remains relatively suspended no matter where the head is positioned.

4. Finally, use 1/4″ plastic spiral wrap (I tried 1/8″ and it is too tight) to cover the entire length of the cable.

If I can only get my regular day job of late done, I’ll be able to get to this fun stuff! 😉 And a new post with video will be there soon. This works fairly well so far but I remain convinced it is just an interim solution — something better is needed for the long term.

To test this new machine, I used a “trivase” model which is fairly good for finding faults in sidewall consistency and Z wobble problems. Because my first test model didn’t stick very well to the build plate, I used a thin coating of 3D Systems Cube(tm) Magic glue – this stuff is nearly clear and is not PVA like Elmers but still is water soluble. After hairspray and Kapton tape, this is my favorite bed stick materal. I let the machine run overnight. Next morning, though the job was “done,” this is what I saw in the machine – a partially completed vase. What happened? Turns out, I had a filament tangle in the spool. This is that tangle… and the filament had snapped inside the machine, running out as it kept trying to build – an airprint of sorts.

I detangled this mess, reloaded the filament and then tried to start another job. But something was not right. The extruder would work at the front of the machine, but not the back? Bed leveling issue??? I thought the Z probe autolevel was supposed to fix this (more on that later). However, as I went to check the Z height offset things were not working like it had originally. The extruder motor was making weird noises. No, this was not a filament jam! While you can’t see it, what happened was the wiring in the extruder motor connector had been compromised by the stress at that connector and the movement of the umbilical cord. There is no strain relief here. Look closely at the distance between the nylon wire wrap and the motor connector – that is how it is built. So as the head moves, the wires are getting bent and stressed, and the result is a broken connection. I could actually see a tiny spark in the end of the motor connector on the left-most wire where it is attached to the crimped terminal. While you can see I’ve changed out the larger plastic cable cover with flexible spiral wrap, the issue will come no matter what you do here – the attachment point and movement of the head will break these wires sooner or later. My 12 hour overnight run definitely found this weakness. I’m going to reattach the connector and figure out some added strain relief bracket to keep the umbilical cord from tugging on that part.

One last thing – the XY gantry has NO metal bearings. Just plastic on the metal rods – plenty of grease – but this design was not meant for the long term. Maybe OK at $349 but at $599 there are better built machines. I will say the extruder is a huge step forward – easy to clean for one. The shroud comes off, and another thumbscrew removes the half-plate on the left – the result is this: You can access the drive wheel and the lower part easily, and the extruder falls free of the drive block. Do be careful! I did this while it was hot to insure that I could get rid of any melted plastic along the way. This design is remarkably clean and should perform well. It also appears that this extruder will work with the TEM materials like Ninjaflex(tm) but that remains a test for another day. And one other positive thing – the Z axis screw appears to be an Acme thread instead of the classic threaded rod approach, but I need to do some digging into the machine to confirm that. Thanks to the Z probe report, I do know that my bed is more than 2mm lower in the front than the back – I plan to investigate that too. More to come as I work with this machine.

UPDATE: Some have asked if this machine has a cabinet filter and fan, and its amazing – it does! It appears to have a carbon activated filter mesh, but I’ll need to dig deeper into the box. I have it almost completely disassembled at this point, figuring I might as well do a thorough internal inspection while looking for useful enhancements. One is the insulation on the heat bed pad underneath; in checking it I found it already was coming loose from the corners. It is just glued on – so first I’m going to fix it with some Kapton tape at the edges. I also recentered it – the original installation was obviously hasty.

UPDATE 2: The machine is now fully repaired and ready to go. I added the heated bed insulation underside, repaired the motor connector wiring, added some strain relief and reworked the layout of the umbilical cord to the head. One additional idea I had was to put a pad of ceramic wool insulation between the top of the head block and the extruder – keeping some radiated heat from getting to the upper section. As I’ve only used the factory supplied ABS for now, I need to try some other filament and see how it goes. As soon as I get more results I’ll post them here.

Well, it finally came. The box was in decent shape, despite its long journey from China. I will not post unboxing pics simply because there are plenty of others out there already, though I’m in the first wave (batch of 200) that were shipped to consumers. Thankfully I had the benefit of several others that got theirs Tuesday or Wednesday this week and posted their trials and tribulations.

The interesting thing about mine was like the old “prize in the Cracker Jack box.” You knew there was one in there, but where? Yes, my Press had a special “prize” inside all the way from China! As I unpacked it, I noticed a bit of tangled extruded filament at the left rear corner of the build envelope. But as I went to extract this obviously extraneous stuff, I heard a noise of like a piece of plastic dropping inside the machine. Well, it turned out that they left the test print inside the machine, and with shipping, it became dislodged. Trust me, it wasn’t easy getting it out – I had to turn the machine upside down and gently shake it. Unlike the SD2/3/4 Brooklyn machines, this one is full of shrouds and panels to hide much of the mechanics. The picture to the left is when it was upside down – figured it would be interesting to show how the heated bed is constructed – and look mom, no insulation on the lower side. That is something I plan on fixing soon.

Some early folks reported a loose extruder drive wheel set screw. I checked for this and it was OK. I also had some issues with the Z offset calibration process. The machine can in fact automatically deploy and stow the probe, but it didn’t when I started the Z offset routine and the bed crashed into the head. I always have a close hand on the power cord…. so by connecting the Press to Repetier (yes, this is easily done) I was able to lower the bed and get things unjammed. The machine didn’t seem fazed at all by this mishap, but it could happen to anyone. After getting the probe down manually, the offset test worked fine and I kept the factory settings. Also, mine has the Y homing jam issue – it behaves like it doesn’t activate the switch at the end of Y travel (to the rear of the machine). Homing the Y axis results in the gantry crashing into the rear while the motor continues to attempt to move it. So one of my investigations will be to find out what is going on here with that part of the machine, unless somebody else out there finds it first and posts it. (got it, see below – the head umbilical cord gets jammed between the head and the back of the case – another “upgrade” to do….)

Yes mine also had a messy extruder block, apparently from burn in and testing. You’d think a small QC step would be to brush off the deposits before cooling down and packing it for shipping.

As for the Solipress software, it is as advertised – minimal control. One thing it needs (besides getting the 10 or so posted bugs fixed) get a more obvious manual axis control. You can send it G code – it is in the “printer options” panel. My first build warped off the plate (just using it as received – time to get some AquaNet hairspray). But when I stopped the build, the Z stage just sat there. How do you get it to move downward to some usable depth so that you can access and clean the build plate? And, there is no option to create a raft in the slic3r configuration (but you can turn on supports!). Given the delays in getting this machine to buyers, I’d think the software would have been fairly polished and debugged long ago.

So I’ll continue to test this and let you know how it works. Stay tuned! Here is a picture of the “Prize in every Box” – the stray filament (I think from the Z axis offset calibration) and the test print. That test print, BTW, is not too well done…

UPDATE #1: The nasty Y homing problem is actually a design flaw. Using Repetier and manually sending some simple G code (M119 – report endstop status) I was able to confirm that the issue is not the endstops. They are working just fine. The problem is the large diameter cable cover to the head – it falls down behind the head and gets in the way of the gantry as it moves back to the rear where the Y limit switch is located. The cable cover is really too stiff and large and just doesn’t stay up in the top of the chassis. My plan is to replace it with some smaller diameter cable spiral, and fix one end of it at the rear so it stays out of the way when the gantry moves to the endstop. This will definitely fix it. I can move the gantry manually to the endstop so long as there isn’t the obstruction from the head cable. I’ll update this when I have the fix in place to show you how I did it. Also, the Z “home” is actually the Z probe, so homing in the normal sense can’t be done unless the probe is deployed before doing the homing of the Z axis. If you don’t, crash! The Z motor will just keep driving the platen into the extruder tip and that is not good! So some thought to how you home the Z is in order before using some other software like Repetier (though Solidoodle has released a Repetier customization that includes the new Press).